Historically, integrated circuits (ICs) have comprised a semiconductor die supported by a conductive lead frame. As illustrated in FIG. 1, the typical IC 10 has lead frame leads 12 and a paddle 14, a die 16 having a front side with circuitry and a back side, bond wires 18, and encapsulation material or layer 20. Bond wires 18 attach to bond pads (not shown) on the front of the die 16. Bond wires provide the connection between the IC die and the lead frame leads which are attached to printed circuit boards (PCBs) or other devices (not shown).
The semiconductor industry pursues cost effective and reliable methods to decrease the size of semiconductor packages. The development of the dual in-line package (DIP) has been instrumental in the development of thin small outline packages (TSOPs), tape automated bonding (TAB), and chip on board (COB) technologies.
COB assembly processes typically include the steps of bonding a die to a substrate and interconnecting the die to the substrate, using either conventional wirebond or TAB methods.
In reference to FIG. 1, TAB technology has eliminated the lead frame leads 12 and paddle 14 and uses a "tab tape." Tab tapes comprise a pre-designed network of electrical lines and buses which are attached to an IC die. The use of tab tape and the elimination of lead frames save on fabrication steps and costs. Typically, the die is connected to the tab tape by a thermocompression or thermosonic bonder.
The prior processes have various disadvantages. Specifically, the testing of IC chips occurs after the tab tape is attached to a number of die and to the substrate. Thus, when reliability testing takes place, any defective die would require replacement, which would increase costs. Additionally, by using these processes, several steps occur while the die is unprotected or not encapsulated resulting in additional die defects from increased exposure to the environment.
It is noted that the above-described problems, as well as other problems, are solved through the subject invention and will become more apparent to one skilled in the art from the detailed description herein.